Naphthoylene-aryl-imidazol-peri-dicarboxylic acid, a process of preparing it and intermediate product obtained during ths process



Patented May 23, 1933 UETED STATES ATENT- OFFICE WILHELIVI ECKERT AND OTTO BRA'UNSDORF, OF FBANKFORT-ON-THE-MAIN-HOCHST, GERMANY, ASSIGNORS TO GENERAL ANILINE WORKS, INC., 0]? NEW YORK, N. Y., A

CORPORATION OF DELAWARE NAPHTHOYLENE-ARYL-IMIDAZOL-PERI-DICARBOXYLIG ACID, A PROCESS OF PREPAR- ING IT AND INTERMEDIATE PRODUCTDBTAINED DURING T'I-IS PROCESS N'o Drawing. Application filed May 29, 1929, Serial No; 367,113, and in Germanylune 18, 1928.

The present invention relates to naphthoylene-aryl-imidazol-peri-dicarboxylic acids, a process of preparing them and intermediate products obtained during this process.

Vie have found that naphthoylene-arylimidazol-peri-monoor di-alkyl indandions of the following general formula:

wherein R stands for an aromatic nucleus bound in two adjacent positions to the nitro gen atoms, which nucleus may contain substituents, X for hydrogen or alkyl and X for alkyl can easily be converted into the corresponding naphthoylene-aryl-iinidazolpjcfri-dicarboxylic acids or anhydrides there 0 The process is carried out in the following manner:

The said indandions are heated, advantageously to the boiling point, with concentrated aqueous alkali, whereby the following reaction takes place:

N N N N N N 00 v 00 i or t n or i 0( 0 H006 o at door:

o on no X1/ X2 X1/\X2 X1/'X2 wherein R- stands for an aromatic nucleus bound in two adjacent positions to the nitrogen atoms, which nucleus may contain substituents, X for hydrogen or alkyl and X,

for alkylf It is a surprising fact that while treating with strong alkali at boiling temperature the naphthoylene-aryl-imidazol ring is not likewise split up. 1

It is easy to obtain the naphthoylene-arylimidaZol-peri-dicarboxylic acids from the above described intermediate products namely from the naphthoylene-aryl-imidazol- Malkyl-or dialkyl acetyl)-5-carboxylic acids by treating them, advantageously in the pres ence of a solvent, with an oxidizing agent while gently heating on the water bath. As oxidizing agents there may be used potassium permanganate, sodiumor potassium bichromate chromic acid or the like. The solvent tobe chosen depends on the oxidizing agents used; there can be applied water, caustic soda solution, glacial acetic acid, sul furic acid or the like.f

The new products thus obtained, namely the naphthoylene-aryl-imidazol-peri-dicarboXylic acids aswell as the naphthoylenearyl-i1nidazol-4(alkylor dialkyl-acetyl) 5- carboxylic acids formed as intermediate products have the following general formula:

stituents, Z for a hydroxy aliphatic group.

The new compounds are valuable intermediate products for the manufacture of dyestuffs.

The above mentioned peri-dicarboxylic acids may also be obtained by condensing the acenaphthalic acid described by Freund and Fleischer (cf. Liebigs Annalen vol. 399, page 223) with ortho-diamines and subsequently oxidizing the condensation products in a suit able manner. It is very surprising that by group or for an this oxidation as well as by the above d'escribed oxidation process the naphthoylenearyl-imidazol nucleus is not split up likewise.

The naphthoylene aryl imidazol peri mono- (or di-) alkyl indandions used as starting materials in our present process are obtainable by oxidation of the mono- (or di-) alkyl-peri-indandions of. acenaphthene (described by Freund and Fleischer in Liebigs Annalen vol. 373, page 324 and VOl. 399, page 219) and subsequent condensation of the resulting naphthalene-4:.5-mono- (or dialkyl-- indandion-1.8-dicarboxylic acids and anhydrides respectively with ortho-diamines.

The reaction takes the following course:

The following examples serve to illustrate our invention, but they are not intended to limit it thereto; the parts being by weight.

(1) The starting'material used in this example is the naphthalene-4.5-diethyl-indandion-lB-diCarboxylic acid or the anhydride thereof which easily may be obtained by oxidizing the acenaphthdiethyl-indandion with sodium bichromate in a solution of glacial acetic acid. When using sulfuric acid of between 35 and 45 B the reactionproceeds as well as when using glacial acetic acid. The anhydride crystallizes from glacial acetic acid in short, thick, faintly yellowish prisms melting at between 168 C. and 17 0 C.

The condensation with ortho-phenylenediamine very easily takes place in a solution of glacial acetic acid and yields the naphthoylene-benzimidazol-peri-diethylindandion as shining yellow crystalline laminae having a melting point of 254 C. to 256 C. It dissolves in concentratedsulfuric acid to a yellow solution without any flourescence. The product can, furthermore, be reduced to a vat by means of caustic soda solutionand hydrosulfite and yields a greenish vat from which, however, it hardly dyes the cotton fiber.

One part of naphthoylene-benzimidazolperi-diethyl-indandion of the following probable formula:

solution while passing air through it in order to precipitate at the same time the indandion which has not been split up but which has nevertheless been dissolved in the melt as leuco compound by a reducing action, filtering by suction and precipitating with a dilute mineral acid. The naphthoylene-benzimidazol-L- diethyl-acetyl-5-carboxylic acid of the following probable formula l /N 00 o I HOOC o precipitates in the form of dark yellow flakes and represents after being dried a yellow powder; it dissolves in organic solvents such as ethyl-alcohol or glacial acetic acid, to a reddish-yellow solution and in concentrated sulfuric acid to a red solution. In sodium carbonate solution or a diluted alkali it dissolves to a yellow solution; the sodium salt can be salted out and forms a yellow precipitate.

The oxidation to naphthoyIene-benzimida- Ibo lbs

zol-peri-dicarboxylic acid is carried out as follows:

(a) 2 parts of naphthoylene-benzimidazol- 4-diethylacetyl-5-carboxylic acid, obtained in 5 the above described manner, are dissolved in an equivalent quantity of caustic soda solution of about 10% strength, while heating, and a solution of about 10% strength of about 5 parts of potassium permanganate is gradually added at water-bath-temperature. The oxidation occurs rather rapidly while the solution assumes a green coloration; this green coloration, which is caused by intermediarily formed potassium maganate,

finally disappears again, the potassium maganate splitting off manganese peroxide and thus having an after-oxidizing effect.

The solution, which is now yellow, is filtered from the manganese peroxide and 0 acidified. The naphthoylene-benzi1nidazolperi-dicarboxylic acid separates as a reddishyellow water-insoluble precipitate; it crystallizes from glacial acetic acid, in which it is rather difficultly soluble even while hot, in the 5 form of its anhydride as an orange yellow crystalline powder which assumes a yellow coloration when heated to 270 C. and which does not yet melt at 300 C. It dissolves in concentrated sulfuric acid to a faintly yellow 0 solution.

(1)) parts of the crude product of naphthoylene benzimi-dazol--diethylacetyl-F)-car boxylic acid are dissolved by heating in 8-10 times their weight of glacial acetic acid and 5 -35 parts of sodiumbichromate are slowly added while the solution is gently kept at boiling temperature. A, solution of the oxidizing agent in glacial acetic acid may also be added drop by drop. After a short 0 time already the oxidation product which is only very difficultly soluble in glacial acetic acid begins to precipitate in the form of small yellow little-crystals. After the reaction is finished, the crystals are introduced 5 into diluted sulfuric acid, the liquid is filtered with suction and the crystals are freed from the chromate by washing them with water. By boiling with glacial acetic acid there is from the crude product the naphthoylene benzimidazol-peri-dicarb oxylic anhydride in a pure state as an orange yellow crystalline powder which scarcely dissolves in organic solvents. It has the same properties as described under (a) The melting point of the pure product lies still above 350 C. The contents of nitrogen were determined 8.03%, the contents'ofthe acid (L I-T O N were calculated 7.82% and the contents of its anhydride C2 H O N 823%.

YVhen starting instead of from the naphthoylene benzimidazol peri diethylindandion mentioned in Example 1 from indandions the benzene nucleus of which issubstituted or replaced by another hydrocarbon a residue or from indandions. having instead obtainable by condensing naphthalene-4.5- diethylindandion-1.8-dicarboxylic acid or its anhydride, with 4- chloro 1.2 diaminobenzene. The temperature of the molten mass is gradually raised to about 180 C. and maintained there until a test portion dissolved in water only yields a minute precipitate of unaltered indandion when being thoroughly shaken with air.

The reaction product is isolated as indicated in Example 1. It is a brownish-yellow amorphous substance, rather easily soluble in organic solvents such as glacial acetic acid, ethyl alcohol or acetone more diflicultly soluble in benzene. I It dissolves in concentrated sulfuric acid to reddish-yellow solution. The acid is readily soluble to a yellow solution in sodium carbonate solution, diluted alkalies or dilute aqueous ammonia.

I 10 parts of naphthoylene e chloro -benzimidazoll-diethyl-acetyl-5-carboxylic acid of the following probable formula:

in glacial acetic acid, are introduced gradually at a temperature of between 80 C. and

90 C. After the oxidation is finished, the s0- lution is given into Water, acidified subse quently with sulfuric acid,.boiled, the yellow precipitate is filtered with suction and rinsed with water. It consists for the most part of the anhydride of the naphthoylene-chlorobenzimidazol-peri-dicarboxylic acid of the following probable formula Hoot tool; by boiling with glacial acetic acid the anhydride can be obtained in a pure state as a wherein R stands for a bivalent aromatic radical of the benzene series bound in othopositions to the nitrogen atoms, X for hy drogen or alkyl and X for alkyl, with concentrated aqueous caustic potash and treating the intermediate product thus obtained with sodium bichromate in the presence of acetic anhydride.

3. The processwhichcomprises heating a compound of the following formula:

a wherein Y stands for hydrogen or chlorine, X for hydrogen or alkyl and X for alkyl, with concentrated aqueous alkali and treating the intermediate product thus obtained with an oxidizing agent in the presence of a diluent while gently heating.

4. The process which comprises heating to boiling temperaturea compound of the following formula:

3; X1 2 wherein Y stands for hydrogen or chlorine, X for hydrogen or alkyl and X for alkyl. with concentrated aqueous caustic potash and treating the intermediate product thus obtained with sodium bichromate in the presence of acetic anhydride.

5. The process which comprises heating naphthoylene benzimidazol peri diethylindandion with concentrated aqueous alkali and treating the intermediate product thus obtained with an oxidizing agent in the presence of a diluent while gently heating.

6. The process which comprises heating to boiling temperature naphthoylene-benzimidazol-peri-diethyl-indandion with concentrated aqueous caustic potash and treating the intermediate product thus obtained with sodium bichromate in the presence of glacial acetic anhydride. 7

7. As new products, compounds of the fol- Z stands for a hydroxy group or for the lowing formula:

Hoot; o

wherein R stands for the bivalent radical:

O I I in which R stands for a bivalent aromatic radical of the benzene series bound in orthopositions to the nitrogen atoms, Z for a hy- ClIOXl group or for the group X being hydrogen or alkyl, X being alkyl. 8. As new products, compounds of the following formula:

Y for hydrogen or chlorine, Z for a hydroxi group or for the group X being hydrogen or alkyl, X being alkyl. 9. As new products, compounds of the fol lowing formula:

wherein R stands for the bivalent radical:

radical 10. As a new product, naphthoylene-benzimidazol-peri-dicarboxylic acid being a reddish-yellow product which crystallizes from glacial acetic acid in form of its anhydride as an orange-yellow crystalline powder melting at a temperature about 350 C. and dissolving in concentrated sulfuric acid to a faintly yellow solution.

11. As a new product, naphthoylene- 8O chloro-benzimidazole-peri-dicarboxylic acid of the following probable formula:

of? l E00 OOH OTTO BRAUNSDORF. 

